When an atom gains a valence electron, it becomes a(n) ion. a, positive
b, negative
c, neutral
d, polyatomic

The atom on gaining an electron to attain the stable configuration and assigned a negative charge. Thus option B is correct.

The atom has been the smallest unit of matter. The atom has been consisted of the centrally charged nucleus and the negatively charged electrons revolving around the nucleus.

The electrons have been filled in the orbitals in the order of their energy level. The electrons have been acquired within the shells to attain a stable configuration.

The atoms on losing an electron in order to attain the stable configuration have been assigned with a positive charge.

The atom on gaining an electron to attain the stable configuration and forms a bond has been assigned with a negative charge. Thus option B is correct.

For more information about the charge on atoms, refer to the link:

link

The answer to your question is: negative

Explanation:

When an atom loses electrons, it becomes positive and it's called cation.

When an atom gains electrons, it becomes negative and it's called anion.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).

it would be b. 6co2 + 6h2o --> c6h12o6 + 6o2